“If he should be so fortunate as to succeed in either the one or the other of these points, he will render the most essential benefit to the mining interest of this country, and to the cause of humanity in particular.” After spending a few days in the district with Mr. Hodgson and Dr. Gray, in the course of which he saw and experimented with Dr. Clanny’s lamp, he went on a round of visits in Durham and Yorkshire, and arrived in London at the end of September. Early in October a quantity of fire-damp was sent to him by Mr. Hodgson, the receipt of which he acknowledged on the 15th, saying:-- “My experiments are going on successfully and I hope in a few days to send you an account of them; I am going to be fortunate far beyond my expectations.” Four days afterwards he again wrote to Mr. Hodgson stating that he had discovered “that explosive mixtures of mine-damp will not pass through small apertures or tubes; and that if a lamp or lanthorn be made air-tight on the sides, and furnished with apertures to admit the air, it will not communicate flame to the outward atmosphere.” On the 25th October he gave an account of his work to the Chemical Club. On October 30th he wrote to Dr. Gray and to Mr. Hodgson, giving a description of three forms of _safe lamps_. His letter to Dr. Gray was as follows:-- “As it was the consequence of your invitation that I endeavoured to investigate the nature of the fire-damp, I owe to you the first notice of the progress of my experiments. “My results have been successful far beyond my expectations. I shall enclose a little sketch of my views on the subject; and I hope in a few days to be able to send a paper with the apparatus for the committee. I trust the _safe lamp_ will answer all the objects of the collier. “I consider this at present as a private communication. I wish you to examine the lamps I have had constructed, before you give any account of my labours to the committee. “I have never received so much pleasure from the result of any of my chemical labours; for I trust the cause of humanity will gain something by it.” Mr. Hodgson’s letter was shown to several persons, and appears to have been copied by some, on or about November 2nd, and an extract from it appeared in Dunn’s “View of the Coal Trade.” On November 9th Davy read his first paper on the subject before the Royal Society; it was entitled “On the fire-damp of coal mines, and on the methods of lighting the mines so as to prevent its explosion.” After describing the manner in which his attention had been specially called to the subject, he states that he first made experiments with a variety of phosphori (Kunckel’s, Canton’s, and Baldwin’s), and also with the electrical light in close vessels, in the hope that they might be found to afford the requisite amount of illumination; but the results were not encouraging.